Shift gear, specifically for motor vehicles

ABSTRACT

A shift gear, specifically for motor vehicles, has a main shaft (9) and an auxiliary shaft (8). Arranged on these shafts are several gear groups (56), (7); (14), (15); (16), (17), with two gears each being constantly in mesh. For shifting the gears, sliding sleeves (12), (13) are arranged on the main shaft (9), one of these sleeves at a time being positively couplable to one of the gears (56), (14), (16). To synchronize the sliding sleeve to be engaged, either a retarding device (20) or an accelerating device (46), (50) acts on the main shaft (9), depending on the direction of shift. A planetary gear train (50), which may be part of said accelerating device, has a gear component (22) which can be retarded by means of a friction brake (24) and forms a clutch device for interrupting the flow of power from an engine (51) to an output shaft (27). Serving also the starting, the clutch device is arranged on the transmission output. A shift clutch (29) is provided between the output shaft (27) and the brake rotor (24).

The invention concerns a shift gear for power transmission from anengine to an output shaft, specifically for motor vehicles. Thetransmission of power occurs in such transmissions through positiveshift elements. Absent are thus the frictional shift elements used inother transmissions, which in disengaged conditions cause power losses.

The invention is based on the German patent application No. P 34 17504.0, not previously published. The shift gear described there has inaddition to a central main shaft two auxiliary shafts. The inventionaltransmission may as well feature two auxiliary shafts. However, a designwith only one auxiliary shaft is possible as well. Designing such shiftgears with two auxiliary shafts is frequently desirable because, due tothe branching of power possible thereby to two oppositely disposed meshsystems, it is possible to reduce the width of the gears and thus makethe entire transmission smaller in length. Besides, the radial forcesacting in pairs on the gears of the central main shaft counterbalanceone another. The main shaft is thereby free of radial load.

The shift gear described in the above patent application possesses onthe input end, for doubling the number of speeds, an intermediate shiftgear and a pertaining double shift clutch. The latter is designed as aso-called dry friction clutch; that is, it is accommodated in a dryspace for the transmission housing. Moreover, a central synchronizingdevice is provided on this shift gear for producing synchronism on therespective sliding sleeve to be engaged.

The synchronizing device comprises an accelerating device and aretarding device, both acting on the auxiliary shaft or on bothauxiliary shafts. An electric controller is provided for automaticcontrol of the sliding sleeves, the double shift clutch, and the centralsynchronizing device.

Still unsatisfactory on the shift gear described above is that at leastpart of the gear shift operations--despite automatic electricalcontrol--takes too much time, so that the flow of power is interruptedfor too long a time.

The problem underlying the invention is therefore to improve the shiftgear so that the shift operations will be completed within a timeshorter than heretofore.

The clutch device for interrupting the flow of power from the engine tothe output shaft is inventionally arranged on the transmission output,so that the auxiliary shaft(s) and the gears which are in mesh with theauxiliary shaft gears while arranged on the main shaft are constantlycoupled with the engine. If both the entirety of sliding sleeves and theclutch device are disengaged, only the main shaft will rotate,irrespective of the transmission input speed and irrespective of thetransmission output speed. This makes it now possible to have thecentral synchronizing device act on the main shaft just mentioned. Owingto its much smaller rotating mass as compared to that of the auxiliaryshaft(s) and of the gears rotating with it, the main shaft can beretarded or accelerated much faster in the synchronizing process. Thetime duration for the shift operations is considerably reduced thereby,and the shift operation is simplified. As a result, specifically thetime duration of the power flow interruption is reduced, so that theautomatic transmission control will operate more dependably than before.

As previously known as such from the German Pat. No. 32 06 424, theclutch device arranged on the transmission output comprises a planetarygear set of which one component rotates with the main shaft and anotherwith the output shaft, and of which a third component can be retarded bymeans of a friction brake which may likewise be used for starting. Forone, this enables the safe management of the higher moments occurring onthe transmission output. At the same time, as is previously known aswell from said German patent disclosure, the possibility lends itself toprovide a friction clutch for bridging the planetary gear set. In turn,the clutch device can be used thereby for doubling the number of speedsavailable in the transmission, with a suitable graduation of theplanetary gear.

The central synchronizing device acting on the main shaft features inpreviously known fashion a brake for retarding the main shaft;additionally it may feature--the same as in the initially mentionedshift gear according to patent application No. P 34 17 504.0--anadditionally shiftable gear set for accelerating the main shaft.According to a further idea of the invention, however, an acceleratingdevice for the main shaft will instead be created in that the clutchdevice arranged on the transmission output features a planetary gearwith four components. The planetary gear has thereby a double function:for one, as previously mentioned, it serves to double the number oftransmission speeds and, for another--as part of the centralsynchronizing device, to accelerate the main shafat.

Further inventional designs and embodiments will be more fully explainedhereafter with the aid of the drawing.

FIG. 1 shows schematically an inventional shift gear in longitudinalsection, along with the pertaining controls.

FIG. 2 shows several construction details of the clutch device arrangedat the transmission output, also in longitudinal section.

Marked 51 in FIG. 1, the crank shaft with flywheel 52 connects by way ofa flange 55 with the input shaft 55a of the shift gear, the housing 54of which is flanged to the engine housing 53. Rotating continuously withthe engine, the input gear 56 is in mesh with the gear 7 of theauxiliary shaft 8, by way of whose further gears 15 and 17 the gears 14,16, 18 of the main transmission shaft 9 are driven. The main shaft 9 ismounted as usual in the input gear 56 by way of an antifriction bearing10 and forms together with the ring gear 11, arranged on the other end,a unit. The present example concerns a 6-speed, pneumatically operatedshift gear where three forward speeds and one reverse speed are shiftedby sliding sleeves 12, 13 and a doubling of the number of forward speedsis obtained through the planetary shift gear which is arranged on thetransmission output. For shifting, one of the sliding sleeves 12 and 13arranged on the main shaft 9 is axially shifted and moved in positiveconnection with the respective speed gear 14, 16 or 18 on the main shaftor with the gear 56 of the input shaft 55a. The sliding sleeves 12 and13 are repositioned by means of selector forks 12₁ or 13₁ throughpistons 12₂ or 13 which are mounted in cylinders 12₃ and 13₃. Bycoupling the sliding sleeve 12 with the speed gear 14, the third orfourth speed is shifted, and connecting the sleeve 13 with the speedgear 16 will shift the first or second speed. In mesh with the gear 17of the auxiliary shaft 8, the gear 19 can shift the reverse gear bycoupling the sliding sleeve 13 with the gear 18. The direct fifth orsixth gear is established by connecting the sliding sleeve 12 with theinput gear 56. The illustrated shift gear comprises only one auxiliaryshaft 8. As known in the art, two such auxiliary shafts may be provided.

The planetary split gear 50 arranged on the transmission output has twoplanetary gear planes. It is driven by way of the ring gear 11 which isintegral with the main shaft 9. It outputs by way of the first-planeplanetary gears 21 mounted on the planet carrier 26. The planet carrier26 connects by way of the output shaft 27 with the inner ring 28 of afriction clutch 29 and powers from there, through the universal joint33, the not illustrated vehicle wheels. The planetary gears 21 are inmesh with the ring gear 11 and with the sun gear 22 which connects byway of a hollow shaft with the outer ring 23 of the clutch 29. Thisouter ring 23 supports the hollow brake disk 24 of a friction brakewhich serves as starting brake and likewise, interacting with theplanetary slit gear 50, serves as a clutch device for interrupting thepower flow from the engine crank shaft 51 to the output shaft 27. Thebrake disk 24 features two disks 24₁ which are equipped with a frictioncoating and engage pneumatically a housing ring 25 by way of an annularcylinder 24₂. The shorting of the planetary split gear takes placethrough the clutch 29, half of its disks sitting on the outer ring 23and the other half on the inner ring 28. The clutch is normally closedin that a disk spring 31 compresses the clutch disk package.

The starting takes place through operation of the brake 24, during whichtime the clutch 29 must be disengaged. This is brought about byadmitting compressed air in the pressure space 30₁ above the piston 30,thereby tensioning the disk spring 31. The operating air for the piston30 of the clutch 29 is fed through a bore in the transmission main shaft9 from a rotary air feed 36 on the input end of the transmission andthrough not illustrated rotary connectors between the shaft sections.

For rotational speed adaptation when shifting down, an electricalcontrol 40 causes compresses air to be fed through the valve 37₆ and theline 20₂ into the cylinder 20₁ of the brake piston 20. The piston 20 hason its end facing the planetary gear a friction lining which is broughtin frictional contact with the drum 11₁ of the ring gear 11, therebyslowing the transmission main shaft 9 down. If the control 40 determinesby comparison of the rotational speed information transmitted by thesensor 34, by way of the line 34₁, and sensor 35, by way of the line35₁, that synchronism is given between the respective sliding sleeve 12or 13 and the speed gear to be shifted, the shift operation is initiatedthrough the pneumatic valves 37₁ through 37₅.

In shifting up, the main transmission shaft 9 is accelerated by thefollowing measures: Provided is a second planetary gear plane havingplanetary gears 43 which are mounted on the mentioned planet carrier 26and mesh outside with the as well previously mentioned ring gear 11, andinside with an additional sun gear 44. The latter is connected with thebrake drum 45 which can be retarded by means of the brake 46. Forrotational speed synchronization, the control 40 (after being instructedto shift) initiates via the electrical line 40₁ the changeover of thepneumatic valve 37₁ operated by solenoid. Consequently, compressed airflows through the line 36₁ and the rotary air feed 36 into the space 30₁of the piston 30, disengaging the clutch 29.

At the same time, compressed air flows through the line 46₂ and throughthe solenoid valve 37₇ (actuated via the electrical line 40₇) into thecylinder space 46₁, engaging the brake 46. This causes the ring gear 11,and thus the main transmisson shaft 9, to accelerate by way of theplanetary gears 43, which via the sun gear 44 bear on the brake drum 45.The same as in shifting down, the shift operation is initiated then bythe controller, upon comparison of the rotational speed informationtransmitted by the sensors 34 and 35, if synchronism exists between therespective sliding sleeve and the respective gear.

Since only the main shaft 9 with the ring gear 11 needs to beaccelerated or retarded during synchronization, the shift operations arecompleted within a relatively short time. Either a manually operatedpush button control or a fully automatic system can be employed forshifting the speeds. The two can be combined in such a way that theactuation is fully automatic and that it can be influenced by a pushbutton control, for instance to prevent an up and/or down shifting on upfrom a specific speed. The shifting operation will be describedhereinafter.

The operator pushes the shift button 6 on the control panel 42, thusinstructing the controller 40 via the line 42₈ to automtically shift upto the highest speed. While still in standstill, with brake 24 andclutch 29 disengaged, the sliding sleeve 13 is thus moved into theshifting claws of the gear 16 in that he solenoid compressed air valve37₅, actuated by the controller 40 via line 40₅, opens and the doublepiston 13₂ in the cylinder 13₃ moves the selector fork 13₁, due tocompressed air being fed through the line 13₄, toward the gear 16.

Moved for starting, the gas pedal 41 is equipped with a sensor 41₁ whoseinformation is transmitted as well to the controller 40 via the line41₂. Upon the rotational speed information from the sensor 34, increasedair pressure is admitted in the operating space of the annular piston24₂ as the engine speed increases, through the compressed air valve 37₈which is fashioned as a control valve and connects by way of the line40₈ with the controller, thereby engaging the brake 24. The vehicle isstarting. Upon reaching a specific engine speed, which is being reportedvia the line 34₁, the controller causes the compressed air to be ventedboth from the cylinder of the annular piston 24₂ of the brake and thespace 30₁, by way of the rotary air feed 36 and the valve 37₁, therebyshort-circuiting the planetary split gear 50 in that the spring 31compresses the disks. This shifts the second speed.

Another instruction from the rotational speed sensor 34 causes pressureto be admitted in the space 30₁, through the valve 37₁, therebydisengaging the clutch 29. Next, the double piston 13₂ moves throughopening of the valve 37₅ into zero position, causing the sliding sleeve13 to release the gear 16. Practically simultaneously, the controlleractuates the valve 37₇ permitting compressed air to proceed into thecylinder 46₁, so that the drum 45 and the sun gear 44 will be retarded.The gearing which becomes effective thereby between the planetary gearmount 26 and the ring gear 11 keeps accelerating the main transmissionshaft 9 until the sensors 34 and 35 report synchronism. Then, compressesair is admitted simultaneously in the cylinder 12₃ by way of the valve37₂ and the line 12₅, and the brake 46 is briefly disengaged by way ofthe valve 37₇ and the line 46₂. The double piston 12₂ pushes the slidingsleeve 12 through the fork 12₁ into the shifting claws of the gear 14.Next, the controller 40 actuates via the electrical line 40₈ the valve37₈, thereby admitting compressed air into the circular cylinder 24₂ andengaging the brake 24. The third speed has now been shifted.

To shift the fourth speed, the brake 24 is disengaged and the clutch 29engaged. For shifting the fifth gear, the clutch 29 is disengaged againand the brake is engaged. Upon completion of the synchronization betweenthe sliding sleeve 12 and the gear 56, the brake 46 is disengaged againand, analogous to shifting from the first to the second speed,compressed air is admitted, through actuation of the valve 37₃, in thecylinder 12₃ for moving the double piston 12₂ and the fork 12₁ withsliding sleeve 12 toward the gear 56. Once the sliding sleeve 12 and thegear 56 are in mesh, the brake 24 is engaged again. A subsequent signalfrom the rotational speed sensor 34 again causes the brake 24 todisengage and likewise the clutch 29 to engage by venting the pressurespace 30₁. Thereafter, the sixth gear has been shifted.

The downshift operation is initiated by the controller at a specificengine speed, programmed in the controller, governed by the gas pedalposition. The pertinent information is signaled to the controller by therotational speed sensor 34 and the travel sensor 41.

To shift from the sixth to the fifth speed, the controller disengagesthrough actuation of the valve 37₁ the clutch 29 and engages the brake24 through actuation of the valve 37₈, thereby shifting into fifth gear.The necessary speed synchronization between the sliding sleeve 12 andthe gear 14 occurs in shifting down from fifth to fourth gear in thatthe controller disengages the brake 24 through actuation of thepneumatic valve 37₈ and disengages the sliding sleeve 12 from the gear 6through actuation of the valve 37₃. Next, the controller actuates thevalve 37₆ and admits compressed air on the piston 20, thereby retardingthe ring gear 11 with the sliding sleeve 12 to a level such that the tworotational speed sensors 34 and 35 will report synchronism to thecontroller. In this instant, the solenoid valve 37₂ is actuated and thesliding sleeve connected with the gear 14. Finally, the brake 24 isengaged again. The fourth gear has now been shifted.

The further shifting from the fourth to the third gear proceeds in thesame manner as shifting from the sixth to the fifth gear, the shiftingfrom third to second gear in the same manner as shifting from the fifthto the fourth gear, and lastly shifting from the second to the firstgear again the same as shifting from the sixth to the fifth gear.

If the operator wants to rev the engine without moving the vehicle, hemust push the zero button on the control panel. In reverse gear, whichcan be shifted only in standstill, the sliding sleeve 13 is connectedwith the gear 19 by actuating the valve 37₄, thereby admittingcompressed air through the line 13₅ into the cylinder 13₃.

The arrangement of the planetary gear on the output end, among otherthings, offers the advantage that the multiple speed gear can bearranged directly next to the flywheel. To increase their efficiency,the brake 24 and clutch 29 are arranged in a dry space. Since the brakeserves as a starting element, both the area of the friction lining 24₁and the surface of the rotating brake element must be so dimensionedthat the output converted to heat in starting will be dissipated by theair and/or the surrounding transmission components without overlyheating the surrounding parts. This problem is considerably easier tosolve with the friction elements arranged on the output end rather thanin the engine flywheel space.

FIG. 2 presents a suitable design of the brake and clutch in conjunctionwith a planetary shift gear featuring only a single planetary gearplane. The arrangement is such that only little axial space is needed soas to keep the overall length of the shift gear short. Besides,attention was paid to arranging wear parts operating in the dry space insuch a way that they can be replaced without removal and disassembly ofthe transmission.

Mounted in the transmission housing 101, the main shaft 102 is equippedwith a disk extension 102₁ on which the ring gear 103 is mounted. In thepresent example, the ring gear 103 features in addition to the internalgearing for the planetary drive also an external gearing intended tomesh with a gear of an acceleration device brake 130.

The end wall 101₁ of the transmission housing 101 supports the outputbearing 106 of the transmission. The ring gear 103 located before theend wall 101₁ is in mesh with the planetary gears 127 which are mountedon the two-part planet carrier 104₃, 104₄ of the output shaft 104. Themain transmision shaft 102 is mounted with its extension 102₂, throughthe intermediary of the double-needle bearing 104₂, in a recess in theoutput shaft 104.

The sun gear 105₃ of the planetary gear set is an integral part of theclutch hollow shaft 105 supporting the clutch outer ring 105₂ and thebrake disk 107 and is supported on the transmission end wall 101₁ by thebearing 106. The clutch flange 111 with the inner ring 111₁ of theclutch 117 is driven by way of the output shaft 104 which is mounted ina recess provided in the clutch hollow shaft 105, on needles 105₄. Theinner ring 111₁ of the clutch is likewise fashioned as a cylinder forreceiving the disengaging piston 112 of the clutch.

The clutch 117 and brake 107 operate in the dry space of thetransmission and are outwardly encased by the brake housing 110 and theclutch lid 118. Having a hollow design, the brake disk is sitting inaxially movable fashion on the teeth 105₁ of the clutch hollow shaft 105and is retained, for starting and shifting, by the two brake liningdisks 108 and 109. These lining disks 108 and 109 are attached tomounting screws 110₁ of the brake housing 110 and are forced on thebrake disk by the annular piston 119, for braking. The annular piston ismounted in a circular piston recess 119₁ of the transmission end wall101₁. The brake housing features recesses 110₂ and 110₃ through whichcooling air, moved by the hollow brake disk in the direction of arrow107₁, is introduced and vented.

The compressed air for disengaging the clutch 117 proceeds from thestationary rotary feed 128 through the transverse bore 102₄, the axialbore 102₃ in the transmission main shaft 102, and the axial bore 104₅ inthe output shaft into the space betwen the disengaging piston 112 andthe clutch flange 111. With the clutch 117 disengaged, the disengagingpiston 112 has the disk springs 113 and 114 stressed to a point suchthat the pressure plate 117₁ mounted on the inner ring 111₁ of theclutch flange 111 is disengaged and the disk package runs freely. Thisis the condition, in which the clutch 117 will be in starting. Next,compressed air regulated by a control valve is passed into the ressurespace between the annular cylinder recess 119₁ in the transmission endwall 101₁, and to the annular piston 119, establishing frictionalengagement between the brake lining disks 108 and 109 and the brake disk107. This causes the sun gear 105₃ to be retained through the clutchhollow shaft 105, and the vehicle drive begins from the ring gear 103through the planetary gears 127, the carrier 104₃, 104₄, the outputshaft 104, the clutch flange 111 and the universal shaft 116 whichpowers the vehicle axle.

With the clutch 117 engaged, i.e., the disengaging piston 112unpressurized, and with the disk package compressed by the disk springs113 and 114, the planetary gear is short-circuited, the drive occursthus directly from the main transmission shaft 102 via the clutch hollowshaft 105, clutch flange 111 and to the universal shaft 16.

The multiple-speed gear need not be opened to change wear parts of thegroup transmission. With the universal shaft 116 removed by looseningthe screws 115, the disk springs 113 and 114 are unstressed afterremoval of the clutch lid 118 and can be removed. Next, the disk packageof the clutch 117 and/or its lined disks are to be replaced. If thelining disks 108 and 109 of the brake are to be replaced as well, thebrake housing 110 must be removed by loosening the screws 110₁, removingthen the lining disks 108 and 109 along with the brake disk 107 andreplacing them. Neither the clutch nor the brake controls need to beremoved for this procedure.

FIG. 1 shows schematically also how, if required, a hydrodynamicretarder 100 can be arranged:

For instance, the speed gear 16 is in mesh with the gear 99; this gearconnecting through an angular gear 98 with the retarder rotor 97. It isessential that the retarder rotor is connected to those transmissionparts whose rotational speed is always proportional to the engine speed.If the retarder rotor were instead coupled with the main shaft 9, itsrotational mass would prolong the time needed for synchronization whenshifting gears.

I claim:
 1. A shift gear arrangement for a motor vehicle transmission,which motor vehicle has an engine;said transmission comprising ahousing, an input shaft, an output shaft, a main shaft and at least oneauxiliary shaft, which transmission is operable to transfer powerbetween said engine and said output shaft; a plurality of gear groups,each of said gear groups having at least two gears which are in constantmesh, said gears mounted on said main shaft and said at least oneauxiliary shaft; each of said auxiliary shaft mounted gears of said geargroups is secured to and rotates with said auxiliary shaft; each of saidmain shaft mounted gears of said gear groups is rotatable on said mainshaft; sliding sleeves mounted on said main shaft, said sleevesnonrotatable about said main shaft and axially slidable thereon toengage and couple at least one of said main shaft mounted gears; aclutch device mounted in said transmission is operable as a startingclutch and to interrupt power transfer from the engine to the outputshaft, said clutch device having a friction brake with a rotor (24;107)and a planetary gear set (50; 120), which planetary gear set has aplurality of gear components including a first component (11; 103)constantly coupled with said main shaft (9, 102), and a second component(22; 105₃) constantly coupled to the rotor (24; 107) of the frictionbrake, and a third component (26; 104₃) constantly coupled to saidoutput shaft (27, 104); a shift clutch (29) mounted in said transmissionand operable between said output shaft (27, 104) and said brake rotor(24, 107); a central synchronizing device including an electroniccontrol and being arranged to provide one of acceleration andretardation of said main transmission shaft via said clutch device atdisengagement of said sliding sleeves, said synchronizing deviceoperable to cooperate with each sliding sleeve to positively couple saidsleeve with at least one gear on said main shaft.
 2. A shift geararrangement as claimed in claim 1 wherein said planetary gear set (50)has first, second, third and fourth gear components, and includes afirst synchronizing brake (20) and a second synchronizing brake(46);said planetary gear set first gear component (11) mouned on androtatable with said main shaft, said first gear component operable to beretarded by said first synchronizing brake (20); said friction brake isoperable to retard said planetary gear set second gear component (22),to serve as a starting clutch and to be coupled to said output shaft bysaid shift clutch (29); said third gear component (26) connected to saidoutput shaft (27); and, said planetary gear set fourth gear component(44) operable to be retarded by said second synchronizing brake (46) toaccelerate said main shaft (9).
 3. Shift gear according to claim 2,characterized by the following features:(a) the first gear component(11) is a ring gear which is engaged by two planetary gear groups (21,43) which are arranged side by side with a common planet carrier (26)and a first sun gear and a second sun gear (22, 44); (b) the second gearcomponent is said first sun gear (22); (c) the third gear component (26)is said planet carrier; and, (d) the fourth gear component is the secondsun gear (44).
 4. A shift gear arrangement as claimed in claim 2 whereinsaid transmission housing defines an end wall in said transmissionhousing which end wall and housing cooperate to define a day spacegenerally in proximity to said output shaft, and downstream of saidplanetary gear set;said friction brake having at least one frictionface; said shift clutch having at least one friction face; said frictionbrake and shift clutch friction faces mounted and operable in said dryspace.
 5. A shift gear arrangement as claimed in claim 4 wherein saidtransmission housing end wall defines a circular cylindrical recess;said friction brake is a full-lining disk brake; and said friction brakehas an operating piston positioned in said circular cylindrical recessand operable to activate said friction brake.
 6. A shift geararrangement as claimed in claim 2 further comprising a spring biasingsaid shift clutch into an engaged position; and,a disengaging pistongenerally centrally mounted in said clutch device, which disengagingpiston is operable to retract said spring and disengage shift clutch. 7.A shift gear arrangement as claimed in claim 6 wherein said motorvehicle includes a drive shaft with a flange; said shift clutch has aninner ring generally defining a cylinder for said disengaging piston;and, said transmission has a clutch lid, which clutch lid and driveshaft flange are screw-mounted on said shift clutch inner ring.
 8. Ashift gear arrangement as claimed in claim 2 wherein said transmissionhas a longitudinal axis; said friction brake includes a hollow brakedisk; and, said shift clutch includes an outer ring with extensions,which hollow brake disk is mounted on said extensions and movable in thelongitudinal axis direction.
 9. A shift gear arrangement as claimed inclaim 2 further comprising a hydrodynamic retarder with a rotor and anangular gear; said angular gear coupled to one of the gears of said geargroups mounted on said main shaft and auxiliary shaft.
 10. Shift gearaccording to claim 1, characterized by the following features:(a) theplanetary gear set has three gear components (103, 104₃, 105₃); (b) thefirst gear component is a ring gear (103) which rotates with the mainshaft (102); (c) the second gear component is a sun gear (105₃)connected with the brake rotor (107); and, (d) the third gear componentis a planet carrier connected with the output shaft (104).
 11. A shiftgear arrangement as claimed in claim 1 wherein said transmission housinghas an end wall in said housing, which end wall and housing cooperate todefine a dry space in said housing, which dry space is generally inproximity to said output shaft, and downstream of said planetary gearset;said friction brake having at least one friction face; said shiftclutch having at least one friction face; said friction brake and shiftclutch friction faces mounted and operable in said dry space.
 12. Ashift gear arrangement as claimed in claim 11 wherein said transmissionhousing end wall defines a circular cylindrical recess; said frictionbrake is a full-lining disk brake, and said friction brake has anoperating piston positioned in said circular cylindrical recess andoperable to activate said friction brake.
 13. A shift gear arrangementas claimed in claim 1 further comprising a spring biasing said shiftclutch into an engaged position; and,a disengaging piston generallycentrally mounted in said clutch device, which disengaging piston isoperable to retract said spring and disengage said shift clutch.
 14. Ashift gear arrangement as claimed in claim 13 wherein said motor vehicleincludes a drive shaft with a flange; said shift clutch has an innerring generally defining a cylinder for said disengaging piston; and,said transmission has a clutch lid, which clutch lid and drive shaftflange are screw-mounted on said shift clutch inner ring.
 15. A shiftgear arrangement as claimed in claim 1 wherein said transmission has alongitudinal axis; said friction brake includes a hollow brake disk;and, said shift clutch includes an outer ring with extensions, whichhollow brake disk is mounted on said extensions and movable in thelongitudinal axis direction.
 16. A shift gear arrangement as claimed inclaim 1 further comprising a hydrodynamic retarder with a rotor and anangular gear; said angular gear coupled to one of the gears of said geargroups mounted on said main shaft and auxiliary shaft.
 17. A shift geararrangement for a motor vehicle transmission, which motor vehicle has anengine;said transmission comprising a housing, an input shaft, an outputshaft, a main shaft and at least one auxiliary shaft, which transmissionis operable to transfer power between said engine and said output shaft;a plurality of gear groups, each of said gear groups having at least twogears which are in constant mesh, said gears mounted on said main shaftand said at least one auxiliary shaft; each of said auxiliary shaftmounted gears of said gear groups is secured to and rotates with saidauxiliary shaft; each of said main shaft mounted gears of said geargroups is rotatable on said main shaft; sliding sleeves mounted on saidmain shaft, said sleeves nonrotatable about said main shaft and axiallyslidable thereon to engage and couple at least one of said main shaftmounted gears; a clutch device mounted in said transmission is operableas a starting clutch and to interrupt power transfer from the engine tothe output shaft, said clutch device having a friction brake with arotor (24, 107) and at least one friction face, and a planetary gear set(50, 120) with a plurality of gear components (103, 104₃, 105₃), thefirst gear component (11, 103) is a ring gear (103) which rotates withthe main shaft (102), the second gear component (22, 105₃) is a sun gear(105₃) connected with the brake rotor (107), and the third gearcomponent (26, 104₃) is a planet carrier connected with output shaft(104); a shift clutch (29) with at least one friction face mounted insaid transmission and operable between said output shaft (27, 104) andsaid brake rotor (24, 107); a central synchronizing device including anelectronic control and being operable to selectively provide one ofacceleration and retardation of said main transmission shaft via saidclutch device at disengagement of said sliding sleeves, saidsynchronizing device operable to cooperate with each sliding sleeve topositively couple said sleeve with at least one gear on said main shaft,said housing having an end wall, which housing and end wall cooperate todefine generally in proximity to said output shaft, and downstream ofsaid planetary gear set a dry space in said housing; said friction brakeand shift clutch friction faces mounted and operable in said dry space.18. A shift gear arrangement for a motor vehicle transmission as claimedin claim 17 further comprising a spring biasing said shift clutch intoan engaged position; a disengaging piston generally centrally mounted insaid clutch device, which disengaging piston is operable to retract saidspring and disengage said shift clutch;said friction brake is afull-lining disk brake and has an operating piston; said housing endwall defining a circular cylindrical recess, said friction brakeoperating piston positioned in said recess and operable to activate saidfriction brake.
 19. A shift gear arrangement for a motor vehicletransmission as claimed in claim 18 wherein said transmission has alongitudinal axis; said friction brake disk is a hollow brake disk; andsaid shift clutch includes an outer ring with extensions, which hollowbrake disk is mounted on said extensions and is movable in thelongitudinal direction.
 20. A shift gear arrangement as claimed in claim18 wherein said motor vehicle includes a drive shaft with a flange; saidshift clutch has an inner ring generally defining a cylinder for saiddisengaging piston; and, said transmission has a clutch lid, whichclutch lid and drive shaft flange are screw-mounted on said shift clutchinner ring.
 21. A shift gear arrangement as claimed in claim 17 furthercomprising a hydrodynamic retarder with a rotor and an angular gear;said angular gear coupled to one of the gears of said gear groupsmounted on said main shaft and said auxiliary shaft.
 22. A shift geararrangement as claimed in one of claims 17-21 wherein said planetarygear set (50) has first, second, third and fourth gear components andincludes a first synchronizing brake (20) and a second synchronizingbrake (46);said planetary gear set first gear component (11) mouned onand rotatable with said main shaft, said first gear component (11)operable to be retarded by said first synchronizing brake (20); saidfriction brake operable to retard said planetary gear set second gearcomponent (22), to serve as a starting clutch and to be coupled to saidoutput shaft by said shift clutch; said third gear component (26)connected to said output shaft (27); and, said planetary gear set fourthgear component (44) operable to be retarded by said second synchronizingbrake (46) to accelerate said main shaft (9).
 23. A shift geararrangement for a motor vehicle transmission, which motor vehicle has anengine;said transmission comprising a housing, an input shaft, an outputshaft, a main shaft and at least one auxiliary shaft, which transmissionis operable to transfer power between said engine and said output shaft;a plurality of gear groups, each of said gear groups having at least twogears which are in constant mesh, said gears mounted on said main shaftand said at least one auxiliary shaft; each of said auxiliary shaftmounted gears of said gear groups is secured to and rotates with saidauxiliary shaft; each of said main shaft mounted gears of said geargroups is rotatable on said main shaft; sliding sleeves mounted on saidmain shaft, said sleeves non-rotatable about said main shaft and axiallyslidable thereon to engage the couple at least one of said main shaftmounted gears; a clutch device mounted in said transmission is operableas a starting clutch and to interrupt power transfer from the engine tothe output shaft, said clutch device having a first friction brake witha rotor (24; 107) and a planetary gear set (50; 120), which planetarygear set has a plurality of gear components including a first component(11; 103) constantly coupled with said main shaft (9, 102), and a secondcomponent (22; 105₃) constantly coupled to the rotor (24; 107) of thefriction brake, and a third component (26; 104₃) constantly coupled tosaid output shaft (27, 104); a shift clutch (29) mounted in saidtransmission and operable between said output shaft (27, 104) and saidbrake rotor (24, 107); an accelerating device for accelerating the mainshaft, and a second friction brake for decelerating said main shaft; acentral synchronizing device including an electronic control and beingarranged to provide one of acceleration and retardation of said maintransmission shaft via said accelerating device and said second frictionbrake, respectively, at disengagement of said sliding sleeves, saidsynchronizing device operable to cooperate with each sliding sleeve topositively couple said sleeve with at least one gear on said main shaft.